1. Field of the Invention
This invention is concerned with shaft seals suitable for installation over an enlarged element without having to use special installation devices or tools and without damage to or excessive stretching of the seal element.
2. Description of the Prior Art
In the past, efforts to install seals over roughened or enlarged areas have been directed primarily to the use of special installation methods and tools rather than to new seal designs. The most common practice has been to employ a seal of standard design but stretched to an enlarged I.D. by means of a tapered hollow sleeve. The sleeve covers the enlarged portion on the shaft and the seal is pushed axially past the enlarged portion. The seal is pushed axially inwardly and then the installation sleeve is withdrawn axially outwardly thus permitting the seal lip to return to its original I.D. and thus into sealing engagement with the shaft. However, in some instances the degree of stretch has been excessive and the seal lip has been damaged. Such excessive stretch can result in a situation where the resilience of the seal lip is insufficient to maintain proper sealing contact with the shaft. In more extreme cases, the seal element may be stretched to the point of splitting. In those cases, a new seal must be substituted. Another problem which can be encountered is damage to the seal lip if there are any nicks or rough spots on the installation tool or sleeve.
Thus, it is an object of this invention to provide a seal which can be installed over a roughened or enlarged area without damage to the seal lip.
It is a further object to provide a seal which can be installed without the use of special installation tools.
Another object is to provide a seal with a deformable shell which is utilized to bring the seal lip into proper sealing engagement with the shaft.
Other objects will become apparent upon consideration of the following detailed description, the accompanying drawings and the appended claims.